Fallout star Ella Purnell's American accent is so good she had to convince co-star she is British

Ella Purnell has reached new heights in recent weeks thanks to the release of Amazon's Fallout.

The video game adaptation starring Purnell, Walton Goggins, and Aaron Moten sits at an hugely impressive 93 percent score on Rotten Tomatoes.

The 27-year-old displays a flawless American accent on the series, as she has previously on shows like the drama Yellowjackets.

But Purnell is actually from London, leading to many online being surprised as to her real nationality.

And they are certainly not alone.

Last month, Purnell spoke to chat show host Jimmy Fallon about how her American accent was so spot-on, it even convinced one of her fellow actors that she was from the US.

"People always get surprised that I'm British which is the highest compliment ever," she told Fallon.

While starring in a film at 16-years-old, the star did her 'first American accent' and decided to keep it up off-set for three weeks - similar to Lady Gaga in House of Gucci - as she thought 'that's what real actors do', leading her co-star to believe 'she was actually American'.

Ella Purnell's American accent is pretty good. (Rich Polk/Deadline via Getty Images)

She added: "Then one day I dropped it. I was tired, I went into my British accent and he didn't believe I was English."

Fallon then added: "He was like 'stop doing this character, you're freaking me out'."

While at first it was 'nice', she said that in order to prove to him that she was, in fact, British, she was 'making him cups of tea, listing the Kings and Queens of England', adding: "Like, how do I prove it to you?"

Purnell was born Whitechapel and raised in the nearby Bethnal Green. And as to why her accent is so good, she credits her dialect coach as the person 'made this'.

As for her acting career, the Fallout star got her big break at the age of 12 as she landed a West End role in the musical Oliver! in 2008.

Ella Purnell in Fallout. (Amazon Studios)

As for Fallout, fans of the original video game series and film fanatics alike cannot get enough of it.

In UNILAD's review, we said that 'Fallout is a brilliant debut season, perfect for fans of the game or simply someone who wants a good fun watch'.

It adds: "It is simultaneously brutal, hilarious, and will have you gripped and desperately waiting for the next episode.

"Don’t walk, run to go watch this show – you won’t be disappointed, and you will probably have a new favourite show on TV."